Does Alzheimer's disease with early onset progress faster than with late onset? A case-control study of clinical progression and cerebrospinal fluid biomarkers

Background: Early-onset Alzheimer's disease (EOAD) is generally thought to have a more rapid course compared to late-onset Alzheimer's disease (LOAD). The faster progression of EOAD observed in some studies has also been thought to correlate with cerebrospinal fluid (CSF) biomarkers. Our clinical experience has not been suggestive of any difference in disease progression; therefore, we decided to investigate whether differences in clinical progression and CSF biomarkers between EOAD and LOAD could be demonstrated. Methods: Case-control study with 42 patients, 21 EOAD and 21 matched LOAD patients. Rates of progression were calculated and these, as well as CSF biomarker levels, were statistically compared. Results: There were no statistically significant differences in clinical progression between the EOAD group and the LOAD group. There was no significant difference in the absolute values of CSF biomarkers, but a tendency towards lower levels of β-amyloid in patients with EOAD was observed. Conclusions: Our findings did not converge with results from the majority of previous studies, which have been suggestive of a faster clinical progression in EOAD. Possibly, the very strict algorithm by which our patients were matched explains our findings. However, the findings should be repeated in a larger study population.